Interference effects of co-generated hydrides of arsenic, antimony, bismuth and selenium on trapping behavior of selenium or antimony hydrides (analytes) within iridium modified, transversely heated graphite tube atomizer (THGA) was investigated. A twin-channel hydride generation system was used for independent separate generation and introduction of analyte and interferent hydrides, i.e. in simultaneous and/or sequential analyte-interferent and interferent-analyte mode of operation. Influence of the analyte and modifier mass, interferent amount, trapping temperature and composition of the gaseous phase was studied. A simple approach for elimination of mutual interference effects by modification of the gaseous phase with oxygen in substoichiometric ratio to chemically generated hydrogen is proposed and suppression of these interference effects is demonstrated. A hypothesis on mechanism of trapping and mutual interference effects is drawn.

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International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Range to an orbiting satellite from a ground reference point (ground station) can be determined by measuring the round trip time for a waveform transmitted to the satellite and returned to the ground station (Turnaround Ranging) and more recently by using the Global Positioning System (GPS). This paper first summarizes and compares the two approaches. The paper then describes and analyzes a new turn-around ranging system which uses a flexible ranging waveform that provides spectral compatibility with existing Military, NASA, and Commercial satellite uplink/downlink signals.

In this thesis, experiments were conducted in the laboratory and the field to determine whether the provision of floral resources to hoverflies could enhance the biological control of aphids. The overall aim was to clarify hoverfly behaviour and ecology in an agroecosystem in order to understand the potential of these insects for biocontrol under a conservation biological control (CBC) regime. A preliminary experiment in New Zealand compared the effect of different coloured water-traps on catches of the hoverflies Melanostoma fasciatum (Macquart) and Melangyna novaezelandiae (Macquart). Significantly more individuals were caught in completely yellow traps than in traps with green outer walls and yellow inner walls or in completely green traps. This suggested that if a measure of hoverfly numbers relating to a particular distance along a transect is required, consideration should be given to the ability of hoverflies to detect yellow traps from a distance. The use of traps that are green outside would more accurately reflect the local abundance of hoverflies, as the insect would be likely to see the yellow stimulus only when above or close to the trap. Also, the addition of rose water significantly increased the number of M. fasciatum caught. From a suite of flowering plants chosen for their ability in other studies to increase hoverfly visit frequencies, laboratory experiments were conducted in France to determine the plant’s effectiveness at enhancing Episyrphus balteatus (De Geer) ‘fitness’, and to evaluate whether adult feeding on flowers was related to performance. Phacelia (Phacelia tanacetifolia Bentham cv. Balo), followed by buckwheat (Fagopyrum esculentum Moench cv. Katowase) and coriander (Coriandrum sativum L.) gave the optimal reproductive potential of female E. balteatus. There was no correlation between pollen and nectar consumption, and there was no discernible positive correlation between the quantity of pollen ingested and the resulting female performance. Phacelia and buckwheat were then studied as resource subsidies in the field in New Zealand. The effect of incorporating phacelia or buckwheat in the margins of 5 m x 5 m broccoli plots was tested for hoverfly activity and floral ‘preferences’. Hoverflies which had fed on phacelia and buckwheat pollen were found up to 17.5 m from the floral strips and females of M. fasciatum and M. novaezelandiae consumed more phacelia pollen than that of buckwheat in the field. These results support the choice of phacelia as an ideal floral resource subsidy in crops for enhanced biological control by these New Zealand species. The need for studying hoverfly movement in a large-scale field experiment was apparent from the field studies, so the next experiment was carried out in a field 450 × 270 m and flies were marked via their ingestion of the pollen of phacelia. The focus was on the proportion of flies having consumed the pollen. Although large quantities of pollen were found in some hoverfly guts, most did not contain phacelia pollen and very few were captured at 50 m from phacelia, compared with numbers at the border of the floral strip. A possible explanation was that hoverflies feed on a large variety of pollen species, reducing the relative attraction of phacelia flowers. Another possibility was that hoverflies dispersed from the phacelia away from the crop. Also, pollen digestion rates are likely to be a factor. Finally, a series of experiments was conducted in the field and laboratory to study hoverfly efficacy through oviposition and larval behaviour. In field experiments, female M. fasciatum and M. novaezelandiae laid more eggs where buckwheat patches were larger; however higher oviposition rates did not lead to improved aphid population suppression. In greenhouse experiments, larvae of E. balteatus could initiate a decline in aphid numbers at the predator: prey ratio 1: 8.3, however this control did not persist. Experiments in the laboratory showed that hoverfly larvae became more active and left the system while aphid numbers declined or numbers of larvae increased. This behaviour was caused by two factors: hunger and avoidance of conspecific larvae. Further experiments showed that the avoidance of conspecifics was caused by mutual interference rather than cannibalism. The results of this work highlight the importance of hoverfly dispersal ability. Given the observations of foraging behaviour of females and mutual interference observed between larvae, and the lack of success in CBC by hoverflies in experiments at the crop scale, it is essential to assess the impact of insect predators and parasitoids at a landscape scale.

Motivés par la demande croissante de services de santé améliorés et à distance, qui tend à augmenter notamment avec une population de plus en plus âgée, et la réduction du coût de l'utilisation des infrastructures réseaux, afin d'assurer des applications de santé temps-réel et à faible débit de données, les réseaux de capteurs médicaux sans fil (WBANs) forment encore un domaine de recherche en forte croissance, notamment avec le développement de WBANs coopératifs. Dans ce contexte, en utilisant les utilisateurs du réseau eux-mêmes en tant que relais on pourrait étendre les infrastructures réseaux existantes, tout en améliorant la capacité du réseau et optimisant l'utilisation du spectre radio. Ainsi, les opérateurs réseaux, qui planifient déjà pour l'intégration de l'internet des objets (IoT) et l'informatique en nuage (cloud), devraient aussi penser à créer un nouveau type de réseau ad hoc mobile, où les utilisateurs du réseau sont utilisés comme des stations de base ad hoc simplifiées, afin de partager l'information en temps-réel entre des personnes colocalisées portant des capteurs corporels. Ce nouveau type de réseau est appelé réseau corporel sans fil (BBN: Body-to-Body Network). Dans un BBN, un appareil radio, collecte les données des nœuds capteurs attachés ou portés par une personne, et les transmet à un appareil récepteur situé sur une autre personne du voisinage, afin d'être traitées ou retransmises à d'autres utilisateurs du BBN. le BBN peut trouver des applications dans divers domaines tels que la santé, les sports d'équipe, le militaire, les divertissements, ainsi que des expériences passionnantes des réseaux sociaux. Fonctionnant dans la bande Industrielle, Scientifique et Médicale (ISM), les liaisons de communication dans un BBN seront très sensibles aux interférences entre les différentes technologies qui partagent le spectre radio limité. Ainsi, l'interférence entre ces technologies devient une préoccupation importante pour la conception de protocoles pour l'utilisateur final du BBN. À ce jour, très peu d'études existent, qui effectuent une analyse en profondeur de ce type de scénario implicant le corps humain dans des communications radio. Le problème d'interférence dans un tel système distribué, doit être abordé avec des mécanismes distribués, tels que la théorie des jeux. Les décideurs dans le jeu sont soit les WBANs formant le BBN ou les opérateurs de réseaux qui contrôlent les dispositifs de communication inter-WBAN. Ces dispositifs doivent faire face à des ressources de transmission limitées (bande ISM) ce qui donne lieu à des conflits d'intérêts. Cette thèse vise à explorer les opportunités pour permettre des communications inter-WBANs en assurant le partage du spectre radio par le biais de deux approches. D'abord, l'atténuation des interférences mutuelles et croisées, et par la conception d'un protocole de routage spécifique BBN utilisé dans une application de contrôle de l'expansion d'une épidémie dans les zones de rassemblement de masse, tels que les aéroports. Dans un premier volet, une approche basée sur la théorie des jeux est proposée pour résoudre le problème d'interférence distribué dans les BBNs. Le jeu d'atténuation des interférences socialement conscient des intérêts de la collectivité (SIM) a une double tâche: à l'échelle WBAN, il alloue des canaux ZigBee aux capteurs corporels pour la collecte intra-WBAN des données, et à l'échelle BBN, il alloue les canaux WiFi aux appareils mobiles pour la transmission et le relais des données inter-WBANs. Deux algorithmes, BR-SIM et SORT-SIM, ont été développés pour rechercher les points d'équilibre de Nash du jeu SIM. Le premier (BR-SIM) assure les solutions de meilleure réponse (Best-response) tandis que le second (SORT-SIM) tente d'obtenir un compromis entre des solutions quasi-optimales et un temps de convergence réduit. (...) / Motivated by the rising demand for remote and improved healthcare, while decreasing the cost of using network infrastructures to ensure time and data rate-constrained applications, Wireless Body Area Networks (WBANs) still form a strongly growing research field. Besides, engineers and researchers are investigating new solutions to supplement mobile communications through developing opportunities for cooperative WBANs. In this context, using network users themselves as relays could complement and extend existing infrastructure networks, while improving network capacity and promoting radio spectrum usage. Yet, network operators, that are already planning for the Internet of Things (IoT) and cloud computing technologies integration, should also think about this new possibility of creating a new type of mobile ad hoc network, where network users themselves are used as simplified ad hoc base stations, to fulfill the desire of sharing real-time information between colocated persons carrying body sensors. This emerging type of network is called Body-to-Body Network (BBN). In a BBN, a radio device situated on one person gathers the sensor data from the sensor nodes worn by that person, and transmit them to a transceiver situated on another person in the nearby area, in order to be processed or relayed to other BBN users. BBNs can find applications in a range of areas such as healthcare, team sports, military, entertainment, as well as exciting social networking experiences. Operating in the popular Industrial, Scientific and Medical (ISM) band, the communication links in a BBN will be heavily susceptible to interference between the different radio technologies sharing the limited radio spectrum. Thus, inter-body interference become an important concern for protocol design and quality of service for the BBN end user. Yet, higher layer MAC and networking mechanisms need to be in place to overcome this interference problem. To date, very few studies, that perform in-depth analysis of this type of body-centric scenario, exist. The interference problem in such distributed system, should be tackeled with distributed mechanisms, such as Game Theory. The decision makers in the game are either the WBANs/people forming the BBN or the network operators who control the inter-WBAN communicating devices. These devices have to cope with a limited transmission resource (ISM band) that gives rise to a conflict of interests. This thesis aims at exploring the opportunities to enable inter-WBAN communications by ensuring feasible sharing of the radio spectrum through two challenging research issues. First, mutual and cross-technology interference mitigation, and second, the design of a BBN specific routing protocol applied to an epidemic control application within mass gathering areas, such as the airport, as use case in this thesis. In a first phase, a game theoretical approach is proposed to resolve the distributed interference problem in BBNs. The Socially-aware Interference Mitigation (SIM) game performs twofold: at the WBAN stage, it allocates ZigBee channels to body sensors for intra-WBAN data sensing, and at the BBN stage, it allocates WiFi channels to mobile devices for inter-WBAN data transmitting and relaying. Two algorithms, BR-SIM and SORT-SIM, were developed to search for Nash equilibra to the SIM game. The first (BR-SIM) ensures best response solutions while the second (SORT-SIM) attempts to achieve tradeoff between sub-optimal solutions and short convergence time. Then, in order to highlight the social role of BBNs, the second part of this thesis is devoted to propose an epidemic control application tailored to BBNs, in indoor environment. This application implements a geographic routing protocol, that differentiates WBANs traffic and ensures real-time quarantine strategies. (...)